Dynamics of fish assemblages on coral reefs subjected to different management regimes in the Abrolhos Bank,eastern Brazil

• 1. Marine protected areas (MPAs) range from multiple‐use areas (MUA) to absolute no‐take reserves (NTR). Despite their importance for fisheries management, there are few long‐term studies comparing benefits from different types of MPAs within the same region.
• 2. Fish assemblages were monitored for five years (2001–2005) in the largest coral reefs in the South Atlantic (Abrolhos Bank, Brazil). Monitoring included one community‐based MUA, two NTRs (one established in 1983 and another in 2001), and one unprotected area. Benthic assemblages at these areas, as well as fish assemblages on unprotected deeper reefs (25–35 m), were monitored from 2003 onwards.
• 3. Habitat characteristics strongly influenced fish assemblages' structure. This, together with the lack of data from before establishment of the MPAs, did not allow an unequivocal analysis of the effects of the MPAs.
• 4. Biomass of commercially important fish, particularly small carnivores, was higher in the older NTR. Biomass of black grouper Mycteroperca bonaci increased by 30‐fold inside NTRs during the study period, while remaining consistently low elsewhere.
• 5. A single herbivore species, the parrotfish Scarus trispinosus, dominated fish assemblages (28.3% of total biomass). Biomass of this species increased in 2002 on the younger NTR and on the MUA, soon after establishment of the former and banning of the parrotfish fishery in the latter. This increase was followed by a decline from 2003 onwards, after increased poaching and reopening of the parrotfish fishery.
• 6. Fish biomass increased in 2002 across the entire region. This increase was stronger in sites closer to deeper reefs, where fish biomass was up to 30‐times higher than shallow reefs: movement of fish from deeper to shallower areas may have played a role.
• 7. The effective use of MPAs in the Abrolhos Bank is still dependent on adequate enforcement and the protection of critical habitats such as deep reefs and mangroves.

Copyright © 2008 John Wiley & Sons, Ltd.     

Morphological and physiological responses and the recovery ability of Paspalum accessions to water deficit and waterlogging

Limited knowledge about the agronomic potential of Paspalum species from the Americas hinders their use in pastures. The response mechanisms to water deficit and waterlogging were studied in five accessions of Paspalum sp. (P. regnellii cv. BRS Guará and BGP 397, P. conspersum BGP 402 and P. malacophyllum BGP 289 and BGP 293) and Urochloa brizantha cv. Marandu. Morphological and physiological traits at the end of the stress and after the recovery period were measured. All Paspalum accessions, especially BGP 289, BGP 402 and BGP 397, and also cv. Marandu, showed survival mechanisms to water deficit. BRS Guará showed adaptive features to waterlogging, although had with a low survival rate to water deficit. Under waterlogging, BGP 289 and cv. Marandu showed reduced growth, and after the recovery period, they presented low plant survival and root recovery. Although growth of BGP 293 was reduced during waterlogging, it presented high tiller survival rate. BGP 293, BGP 402 and BGP 397 showed adaptive potential strategies for waterlogging and water deficit. There is genetic variability among the evaluated accessions for water deficit and waterlogging stresses, suggesting that they may be used per se or as progenitors in crosses with other genotypes in breeding programmes.     

Pollination and in vitro germination of seeds for interspecific hybridization of <Emphasis Type="Italic">Psidium guajava</Emphasis> and <Emphasis Type="Italic">Psidium cattleianum</Emphasis>

The genus Psidium includes important fruit crops. However, there are very few studies focusing on its reproductive biology, which limits the establishment of breeding programs. The present work investigated the reproductive biology of Psidium guajava and Psidium cattleianum in terms of compatibility of crossings between these two species aiming at interspecific hybridization because the latter species is an important source of resistance against the nematode Meloidogyne enterolobii. Several types of crosses were performed to understand the reproductive biology of these species, including the compatibility of intra- and interspecific crossings, using assisted in vivo germination of pollen grains on the stigma. In addition, the in vitro germination of both Psidium species was studied at different stages of fruit development to rescue young seeds to improve the chances of obtaining the hybrids. No fruits of 270 pollinations were obtained on guava buds at the pre-anthesis stage, regardless of the source of the pollen grain and the cultivar used as female genotype. Microscopic analyzes demonstrated the germination of pollen grains and pollen tube growth at crosses between guava cv. ‘Pedro Sato’ (P. guajava) and Psidium cattleianum. High germination percentages of Psidium cattleianum seeds were obtained in MS medium without sucrose or containing 15 g/L of this carbohydrate.     

Wild <Emphasis Type="Italic">Coffea arabica</Emphasis> resistant to <Emphasis Type="Italic">Meloidogyne paranaensis</Emphasis> and genetic parameters for resistance

Arabica coffee production is based on highly productive cultivars; however, these cultivars are susceptible to infestation by several biotic agents, including root-knot nematodes. Collections of wild Coffea arabica germplasm represent an important source of genetic variability for resistant cultivar development. In this study, 1046 plants derived from 71 wild coffee trees were evaluated with respect to Meloidogyne paranaensis resistance. In addition to information on plants reactions, we also evaluated the genetic parameters related to resistance. Progenies from the five most promising plants were also evaluated regarding resistance to M. incognita and M. exigua. The yield potential of selected plants was estimated through analysis of data for fruits harvested in 4 different years. Forty-seven plants were considered resistant based on reproduction factor values. The estimated heritability was high for all analyzed variables leading to substantial selection gain, mainly at the progeny mean level. On the basis of heritabilities and genetic correlations, we conclude that selection could be performed based on values of the gall and egg mass index. However, higher genetic gain could be obtained based on nematode count variables. A second experiment confirmed the reactions of the selected five plants to M. paranaensis, and multiple resistance was detected in three of them. The resistant accessions also have yield potential.     

Susceptibility of eucalypt taxa to a natural infestation by Leptocybe invasa

New Forests - Recently, pest occurrence in forest plantations has been increasing influenced by genotypes and environmental conditions such as climate change, thus impacting production negatively....     

Use of exchangeable and nonexchangeable forms of calcium,magnesium, and potassium in soils without fertilization after successive cultivations with Pinus taeda in southern Brazil

Purpose

The aim of this study was to quantify the contents and stocks of exchangeable and nonexchangeable fractions of potassium (K), calcium (Ca), and magnesium (Mg) after one and three successive Pinus taeda crops without fertilization and to predict the soil supply for further cultivations.

Materials and methods

The soil was analyzed in layers up to 80 cm in two Pinus forests, one at the end of the first cultivation and other at the end of the third successive crop, in a subtropical region in southern Brazil. Stocks of exchangeable and semi-total fractions of K, Ca, and Mg in the soil were calculated, and the potential number of crop rotations of Pinus without fertilization was estimated.

Results and discussion

After three Pinus crops, there was an average reduction of 46.9, 90.8, and 45.5% of exchangeable K, Ca, and Mg fractions respectively. Semi-total Ca content reduced in all depths, and semi-total K contents, in turn, only decreased until 20 cm of depth. The semi-total Mg contents have not been modified over the cultivations. Considering crop management with the export of plant twigs and needles and relying just on the availability of exchangeable Ca, the stocks of these nutrients in the soil would be sufficient for only one more Pinus cultivation, even when considering the absorption of nutrients on an 80-cm soil depth profile.

Conclusions

The management adopted in the region must be modified, replacing the nutrients exported via harvesting, especially Ca. Thus, the establishment of new cultivation of Pinus without fertilization may have its yield impaired, especially by the Ca availability.

     

Biomaterials and Bioactive Natural Products from Marine Invertebrates: From Basic Research to Innovative Applications

Aquatic invertebrates are a major source of biomaterials and bioactive natural products that can find applications as pharmaceutics, nutraceutics, cosmetics, antibiotics, antifouling products and biomaterials. Symbiotic microorganisms are often the real producers of many secondary metabolites initially isolated from marine invertebrates; however, a certain number of them are actually synthesized by the macro-organisms. In this review, we analysed the literature of the years 2010–2019 on natural products (bioactive molecules and biomaterials) from the main phyla of marine invertebrates explored so far, including sponges, cnidarians, molluscs, echinoderms and ascidians, and present relevant examples of natural products of interest to public and private stakeholders. We also describe omics tools that have been more relevant in identifying and understanding mechanisms and processes underlying the biosynthesis of secondary metabolites in marine invertebrates. Since there is increasing attention on finding new solutions for a sustainable large-scale supply of bioactive compounds, we propose that a possible improvement in the biodiscovery pipeline might also come from the study and utilization of aquatic invertebrate stem cells.     

Microbiological quality of Litopenaeus vannamei culture using conventional and biofloc systems

Shrimp farming is a fast‐expanding activity that has supported the growth in the supply of these crustaceans to consumers around the world. However, the end product is vulnerable to contamination at all stages of the process, including the rearing tanks, where current practices prioritize to raise stocking densities and the minimization of water renewal. It is thus important to evaluate the potential of these systems for the proliferation of undesirable microorganisms, which may render the product unfit for human consumption. In the present study, the presence of coagulase‐positive Staphylococcus, Salmonella spp., Vibrio spp., and total and thermotolerant coliforms was verified in biofloc tank and conventional pond systems used for the rearing of Litopenaeus vannamei in Pernambuco, Brazil, and the results were compared with the legislation regulating the marketing of fresh shrimp. Samples were collected from two biofloc tanks with a density of 375 shrimp m^?2, and two conventional ponds with 12 shrimp m^?2. None of the samples tested positive for either Salmonella spp. or coagulase‐positive Staphylococcus, which is consistent with the legislation. While no standards are defined legally for Vibrio spp. or coliforms, very low concentrations were recorded in both systems, in comparison with other studies. While some variation in bacterial contamination was observed over the rearing process, the end product of both systems was fit for human consumption. The results of the study indicate that, while the water is not renewed in the biofloc system, the development of undesirable microorganisms can be controlled, with no adverse effects for the end product.